Many had written him off and tipped Diaz to overcome him with sheer size and ability on the ground but McGregor approached the second of their bouts with more patience than the first.
He sparred with partners mirroring the rangy style of the Stockton fighter and was careful not to expend too much energy early in the fight.
At one-point it looked like McGregor might have exhausted himself as Diaz worked him up against the cage.
A number of decisive body shots from the Irishman changed momentum back in his favour as he appeared to find a second wind.
He trained with Dillon Danis extensively in preparation to improve his ground-game before the fight but never had to call on any of that work.
Despite knocking his opponent down three times, McGregor stuck to his game-plan, stayed on his feet and had his hand raised in a decision win.
Speculation is swirling around the next mega-fight for the Irishman and it remains to be seen whether he will face Diaz again or enter the octagon to defend his featherweight belt.
